blob: ff6155f5e8d9e3e30bbc5fa7422d67119426b1e0 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/fs/nfs/dir.c
3 *
4 * Copyright (C) 1992 Rick Sladkey
5 *
6 * nfs directory handling functions
7 *
8 * 10 Apr 1996 Added silly rename for unlink --okir
9 * 28 Sep 1996 Improved directory cache --okir
10 * 23 Aug 1997 Claus Heine claus@momo.math.rwth-aachen.de
11 * Re-implemented silly rename for unlink, newly implemented
12 * silly rename for nfs_rename() following the suggestions
13 * of Olaf Kirch (okir) found in this file.
14 * Following Linus comments on my original hack, this version
15 * depends only on the dcache stuff and doesn't touch the inode
16 * layer (iput() and friends).
17 * 6 Jun 1999 Cache readdir lookups in the page cache. -DaveM
18 */
19
20#include <linux/time.h>
21#include <linux/errno.h>
22#include <linux/stat.h>
23#include <linux/fcntl.h>
24#include <linux/string.h>
25#include <linux/kernel.h>
26#include <linux/slab.h>
27#include <linux/mm.h>
28#include <linux/sunrpc/clnt.h>
29#include <linux/nfs_fs.h>
30#include <linux/nfs_mount.h>
31#include <linux/pagemap.h>
32#include <linux/smp_lock.h>
33#include <linux/namei.h>
34
35#include "delegation.h"
36
37#define NFS_PARANOIA 1
38/* #define NFS_DEBUG_VERBOSE 1 */
39
40static int nfs_opendir(struct inode *, struct file *);
41static int nfs_readdir(struct file *, void *, filldir_t);
42static struct dentry *nfs_lookup(struct inode *, struct dentry *, struct nameidata *);
43static int nfs_create(struct inode *, struct dentry *, int, struct nameidata *);
44static int nfs_mkdir(struct inode *, struct dentry *, int);
45static int nfs_rmdir(struct inode *, struct dentry *);
46static int nfs_unlink(struct inode *, struct dentry *);
47static int nfs_symlink(struct inode *, struct dentry *, const char *);
48static int nfs_link(struct dentry *, struct inode *, struct dentry *);
49static int nfs_mknod(struct inode *, struct dentry *, int, dev_t);
50static int nfs_rename(struct inode *, struct dentry *,
51 struct inode *, struct dentry *);
52static int nfs_fsync_dir(struct file *, struct dentry *, int);
53
54struct file_operations nfs_dir_operations = {
55 .read = generic_read_dir,
56 .readdir = nfs_readdir,
57 .open = nfs_opendir,
58 .release = nfs_release,
59 .fsync = nfs_fsync_dir,
60};
61
62struct inode_operations nfs_dir_inode_operations = {
63 .create = nfs_create,
64 .lookup = nfs_lookup,
65 .link = nfs_link,
66 .unlink = nfs_unlink,
67 .symlink = nfs_symlink,
68 .mkdir = nfs_mkdir,
69 .rmdir = nfs_rmdir,
70 .mknod = nfs_mknod,
71 .rename = nfs_rename,
72 .permission = nfs_permission,
73 .getattr = nfs_getattr,
74 .setattr = nfs_setattr,
75};
76
77#ifdef CONFIG_NFS_V4
78
79static struct dentry *nfs_atomic_lookup(struct inode *, struct dentry *, struct nameidata *);
80struct inode_operations nfs4_dir_inode_operations = {
81 .create = nfs_create,
82 .lookup = nfs_atomic_lookup,
83 .link = nfs_link,
84 .unlink = nfs_unlink,
85 .symlink = nfs_symlink,
86 .mkdir = nfs_mkdir,
87 .rmdir = nfs_rmdir,
88 .mknod = nfs_mknod,
89 .rename = nfs_rename,
90 .permission = nfs_permission,
91 .getattr = nfs_getattr,
92 .setattr = nfs_setattr,
93};
94
95#endif /* CONFIG_NFS_V4 */
96
97/*
98 * Open file
99 */
100static int
101nfs_opendir(struct inode *inode, struct file *filp)
102{
103 int res = 0;
104
105 lock_kernel();
106 /* Call generic open code in order to cache credentials */
107 if (!res)
108 res = nfs_open(inode, filp);
109 unlock_kernel();
110 return res;
111}
112
113typedef u32 * (*decode_dirent_t)(u32 *, struct nfs_entry *, int);
114typedef struct {
115 struct file *file;
116 struct page *page;
117 unsigned long page_index;
118 u32 *ptr;
119 u64 target;
120 struct nfs_entry *entry;
121 decode_dirent_t decode;
122 int plus;
123 int error;
124} nfs_readdir_descriptor_t;
125
126/* Now we cache directories properly, by stuffing the dirent
127 * data directly in the page cache.
128 *
129 * Inode invalidation due to refresh etc. takes care of
130 * _everything_, no sloppy entry flushing logic, no extraneous
131 * copying, network direct to page cache, the way it was meant
132 * to be.
133 *
134 * NOTE: Dirent information verification is done always by the
135 * page-in of the RPC reply, nowhere else, this simplies
136 * things substantially.
137 */
138static
139int nfs_readdir_filler(nfs_readdir_descriptor_t *desc, struct page *page)
140{
141 struct file *file = desc->file;
142 struct inode *inode = file->f_dentry->d_inode;
143 struct rpc_cred *cred = nfs_file_cred(file);
144 unsigned long timestamp;
145 int error;
146
147 dfprintk(VFS, "NFS: nfs_readdir_filler() reading cookie %Lu into page %lu.\n", (long long)desc->entry->cookie, page->index);
148
149 again:
150 timestamp = jiffies;
151 error = NFS_PROTO(inode)->readdir(file->f_dentry, cred, desc->entry->cookie, page,
152 NFS_SERVER(inode)->dtsize, desc->plus);
153 if (error < 0) {
154 /* We requested READDIRPLUS, but the server doesn't grok it */
155 if (error == -ENOTSUPP && desc->plus) {
156 NFS_SERVER(inode)->caps &= ~NFS_CAP_READDIRPLUS;
157 NFS_FLAGS(inode) &= ~NFS_INO_ADVISE_RDPLUS;
158 desc->plus = 0;
159 goto again;
160 }
161 goto error;
162 }
163 SetPageUptodate(page);
164 NFS_FLAGS(inode) |= NFS_INO_INVALID_ATIME;
165 /* Ensure consistent page alignment of the data.
166 * Note: assumes we have exclusive access to this mapping either
167 * throught inode->i_sem or some other mechanism.
168 */
169 if (page->index == 0) {
170 invalidate_inode_pages(inode->i_mapping);
171 NFS_I(inode)->readdir_timestamp = timestamp;
172 }
173 unlock_page(page);
174 return 0;
175 error:
176 SetPageError(page);
177 unlock_page(page);
178 nfs_zap_caches(inode);
179 desc->error = error;
180 return -EIO;
181}
182
183static inline
184int dir_decode(nfs_readdir_descriptor_t *desc)
185{
186 u32 *p = desc->ptr;
187 p = desc->decode(p, desc->entry, desc->plus);
188 if (IS_ERR(p))
189 return PTR_ERR(p);
190 desc->ptr = p;
191 return 0;
192}
193
194static inline
195void dir_page_release(nfs_readdir_descriptor_t *desc)
196{
197 kunmap(desc->page);
198 page_cache_release(desc->page);
199 desc->page = NULL;
200 desc->ptr = NULL;
201}
202
203/*
204 * Given a pointer to a buffer that has already been filled by a call
205 * to readdir, find the next entry.
206 *
207 * If the end of the buffer has been reached, return -EAGAIN, if not,
208 * return the offset within the buffer of the next entry to be
209 * read.
210 */
211static inline
212int find_dirent(nfs_readdir_descriptor_t *desc, struct page *page)
213{
214 struct nfs_entry *entry = desc->entry;
215 int loop_count = 0,
216 status;
217
218 while((status = dir_decode(desc)) == 0) {
219 dfprintk(VFS, "NFS: found cookie %Lu\n", (long long)entry->cookie);
220 if (entry->prev_cookie == desc->target)
221 break;
222 if (loop_count++ > 200) {
223 loop_count = 0;
224 schedule();
225 }
226 }
227 dfprintk(VFS, "NFS: find_dirent() returns %d\n", status);
228 return status;
229}
230
231/*
232 * Find the given page, and call find_dirent() in order to try to
233 * return the next entry.
234 */
235static inline
236int find_dirent_page(nfs_readdir_descriptor_t *desc)
237{
238 struct inode *inode = desc->file->f_dentry->d_inode;
239 struct page *page;
240 int status;
241
242 dfprintk(VFS, "NFS: find_dirent_page() searching directory page %ld\n", desc->page_index);
243
244 page = read_cache_page(inode->i_mapping, desc->page_index,
245 (filler_t *)nfs_readdir_filler, desc);
246 if (IS_ERR(page)) {
247 status = PTR_ERR(page);
248 goto out;
249 }
250 if (!PageUptodate(page))
251 goto read_error;
252
253 /* NOTE: Someone else may have changed the READDIRPLUS flag */
254 desc->page = page;
255 desc->ptr = kmap(page); /* matching kunmap in nfs_do_filldir */
256 status = find_dirent(desc, page);
257 if (status < 0)
258 dir_page_release(desc);
259 out:
260 dfprintk(VFS, "NFS: find_dirent_page() returns %d\n", status);
261 return status;
262 read_error:
263 page_cache_release(page);
264 return -EIO;
265}
266
267/*
268 * Recurse through the page cache pages, and return a
269 * filled nfs_entry structure of the next directory entry if possible.
270 *
271 * The target for the search is 'desc->target'.
272 */
273static inline
274int readdir_search_pagecache(nfs_readdir_descriptor_t *desc)
275{
276 int loop_count = 0;
277 int res;
278
279 dfprintk(VFS, "NFS: readdir_search_pagecache() searching for cookie %Lu\n", (long long)desc->target);
280 for (;;) {
281 res = find_dirent_page(desc);
282 if (res != -EAGAIN)
283 break;
284 /* Align to beginning of next page */
285 desc->page_index ++;
286 if (loop_count++ > 200) {
287 loop_count = 0;
288 schedule();
289 }
290 }
291 dfprintk(VFS, "NFS: readdir_search_pagecache() returned %d\n", res);
292 return res;
293}
294
295static inline unsigned int dt_type(struct inode *inode)
296{
297 return (inode->i_mode >> 12) & 15;
298}
299
300static struct dentry *nfs_readdir_lookup(nfs_readdir_descriptor_t *desc);
301
302/*
303 * Once we've found the start of the dirent within a page: fill 'er up...
304 */
305static
306int nfs_do_filldir(nfs_readdir_descriptor_t *desc, void *dirent,
307 filldir_t filldir)
308{
309 struct file *file = desc->file;
310 struct nfs_entry *entry = desc->entry;
311 struct dentry *dentry = NULL;
312 unsigned long fileid;
313 int loop_count = 0,
314 res;
315
316 dfprintk(VFS, "NFS: nfs_do_filldir() filling starting @ cookie %Lu\n", (long long)desc->target);
317
318 for(;;) {
319 unsigned d_type = DT_UNKNOWN;
320 /* Note: entry->prev_cookie contains the cookie for
321 * retrieving the current dirent on the server */
322 fileid = nfs_fileid_to_ino_t(entry->ino);
323
324 /* Get a dentry if we have one */
325 if (dentry != NULL)
326 dput(dentry);
327 dentry = nfs_readdir_lookup(desc);
328
329 /* Use readdirplus info */
330 if (dentry != NULL && dentry->d_inode != NULL) {
331 d_type = dt_type(dentry->d_inode);
332 fileid = dentry->d_inode->i_ino;
333 }
334
335 res = filldir(dirent, entry->name, entry->len,
336 entry->prev_cookie, fileid, d_type);
337 if (res < 0)
338 break;
339 file->f_pos = desc->target = entry->cookie;
340 if (dir_decode(desc) != 0) {
341 desc->page_index ++;
342 break;
343 }
344 if (loop_count++ > 200) {
345 loop_count = 0;
346 schedule();
347 }
348 }
349 dir_page_release(desc);
350 if (dentry != NULL)
351 dput(dentry);
352 dfprintk(VFS, "NFS: nfs_do_filldir() filling ended @ cookie %Lu; returning = %d\n", (long long)desc->target, res);
353 return res;
354}
355
356/*
357 * If we cannot find a cookie in our cache, we suspect that this is
358 * because it points to a deleted file, so we ask the server to return
359 * whatever it thinks is the next entry. We then feed this to filldir.
360 * If all goes well, we should then be able to find our way round the
361 * cache on the next call to readdir_search_pagecache();
362 *
363 * NOTE: we cannot add the anonymous page to the pagecache because
364 * the data it contains might not be page aligned. Besides,
365 * we should already have a complete representation of the
366 * directory in the page cache by the time we get here.
367 */
368static inline
369int uncached_readdir(nfs_readdir_descriptor_t *desc, void *dirent,
370 filldir_t filldir)
371{
372 struct file *file = desc->file;
373 struct inode *inode = file->f_dentry->d_inode;
374 struct rpc_cred *cred = nfs_file_cred(file);
375 struct page *page = NULL;
376 int status;
377
378 dfprintk(VFS, "NFS: uncached_readdir() searching for cookie %Lu\n", (long long)desc->target);
379
380 page = alloc_page(GFP_HIGHUSER);
381 if (!page) {
382 status = -ENOMEM;
383 goto out;
384 }
385 desc->error = NFS_PROTO(inode)->readdir(file->f_dentry, cred, desc->target,
386 page,
387 NFS_SERVER(inode)->dtsize,
388 desc->plus);
389 NFS_FLAGS(inode) |= NFS_INO_INVALID_ATIME;
390 desc->page = page;
391 desc->ptr = kmap(page); /* matching kunmap in nfs_do_filldir */
392 if (desc->error >= 0) {
393 if ((status = dir_decode(desc)) == 0)
394 desc->entry->prev_cookie = desc->target;
395 } else
396 status = -EIO;
397 if (status < 0)
398 goto out_release;
399
400 status = nfs_do_filldir(desc, dirent, filldir);
401
402 /* Reset read descriptor so it searches the page cache from
403 * the start upon the next call to readdir_search_pagecache() */
404 desc->page_index = 0;
405 desc->entry->cookie = desc->entry->prev_cookie = 0;
406 desc->entry->eof = 0;
407 out:
408 dfprintk(VFS, "NFS: uncached_readdir() returns %d\n", status);
409 return status;
410 out_release:
411 dir_page_release(desc);
412 goto out;
413}
414
415/* The file offset position is now represented as a true offset into the
416 * page cache as is the case in most of the other filesystems.
417 */
418static int nfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
419{
420 struct dentry *dentry = filp->f_dentry;
421 struct inode *inode = dentry->d_inode;
422 nfs_readdir_descriptor_t my_desc,
423 *desc = &my_desc;
424 struct nfs_entry my_entry;
425 struct nfs_fh fh;
426 struct nfs_fattr fattr;
427 long res;
428
429 lock_kernel();
430
431 res = nfs_revalidate_inode(NFS_SERVER(inode), inode);
432 if (res < 0) {
433 unlock_kernel();
434 return res;
435 }
436
437 /*
438 * filp->f_pos points to the file offset in the page cache.
439 * but if the cache has meanwhile been zapped, we need to
440 * read from the last dirent to revalidate f_pos
441 * itself.
442 */
443 memset(desc, 0, sizeof(*desc));
444
445 desc->file = filp;
446 desc->target = filp->f_pos;
447 desc->decode = NFS_PROTO(inode)->decode_dirent;
448 desc->plus = NFS_USE_READDIRPLUS(inode);
449
450 my_entry.cookie = my_entry.prev_cookie = 0;
451 my_entry.eof = 0;
452 my_entry.fh = &fh;
453 my_entry.fattr = &fattr;
454 desc->entry = &my_entry;
455
456 while(!desc->entry->eof) {
457 res = readdir_search_pagecache(desc);
458 if (res == -EBADCOOKIE) {
459 /* This means either end of directory */
460 if (desc->entry->cookie != desc->target) {
461 /* Or that the server has 'lost' a cookie */
462 res = uncached_readdir(desc, dirent, filldir);
463 if (res >= 0)
464 continue;
465 }
466 res = 0;
467 break;
468 }
469 if (res == -ETOOSMALL && desc->plus) {
470 NFS_FLAGS(inode) &= ~NFS_INO_ADVISE_RDPLUS;
471 nfs_zap_caches(inode);
472 desc->plus = 0;
473 desc->entry->eof = 0;
474 continue;
475 }
476 if (res < 0)
477 break;
478
479 res = nfs_do_filldir(desc, dirent, filldir);
480 if (res < 0) {
481 res = 0;
482 break;
483 }
484 }
485 unlock_kernel();
486 if (desc->error < 0)
487 return desc->error;
488 if (res < 0)
489 return res;
490 return 0;
491}
492
493/*
494 * All directory operations under NFS are synchronous, so fsync()
495 * is a dummy operation.
496 */
497int nfs_fsync_dir(struct file *filp, struct dentry *dentry, int datasync)
498{
499 return 0;
500}
501
502/*
503 * A check for whether or not the parent directory has changed.
504 * In the case it has, we assume that the dentries are untrustworthy
505 * and may need to be looked up again.
506 */
507static inline int nfs_check_verifier(struct inode *dir, struct dentry *dentry)
508{
509 if (IS_ROOT(dentry))
510 return 1;
511 if ((NFS_FLAGS(dir) & NFS_INO_INVALID_ATTR) != 0
512 || nfs_attribute_timeout(dir))
513 return 0;
514 return nfs_verify_change_attribute(dir, (unsigned long)dentry->d_fsdata);
515}
516
517static inline void nfs_set_verifier(struct dentry * dentry, unsigned long verf)
518{
519 dentry->d_fsdata = (void *)verf;
520}
521
522/*
523 * Whenever an NFS operation succeeds, we know that the dentry
524 * is valid, so we update the revalidation timestamp.
525 */
526static inline void nfs_renew_times(struct dentry * dentry)
527{
528 dentry->d_time = jiffies;
529}
530
Trond Myklebust1d6757f2005-06-07 18:37:01 -0400531/*
532 * Return the intent data that applies to this particular path component
533 *
534 * Note that the current set of intents only apply to the very last
535 * component of the path.
536 * We check for this using LOOKUP_CONTINUE and LOOKUP_PARENT.
537 */
538static inline unsigned int nfs_lookup_check_intent(struct nameidata *nd, unsigned int mask)
539{
540 if (nd->flags & (LOOKUP_CONTINUE|LOOKUP_PARENT))
541 return 0;
542 return nd->flags & mask;
543}
544
545/*
546 * Inode and filehandle revalidation for lookups.
547 *
548 * We force revalidation in the cases where the VFS sets LOOKUP_REVAL,
549 * or if the intent information indicates that we're about to open this
550 * particular file and the "nocto" mount flag is not set.
551 *
552 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553static inline
554int nfs_lookup_verify_inode(struct inode *inode, struct nameidata *nd)
555{
556 struct nfs_server *server = NFS_SERVER(inode);
557
558 if (nd != NULL) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700559 /* VFS wants an on-the-wire revalidation */
Trond Myklebust1d6757f2005-06-07 18:37:01 -0400560 if (nd->flags & LOOKUP_REVAL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700561 goto out_force;
562 /* This is an open(2) */
Trond Myklebust1d6757f2005-06-07 18:37:01 -0400563 if (nfs_lookup_check_intent(nd, LOOKUP_OPEN) != 0 &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700564 !(server->flags & NFS_MOUNT_NOCTO))
565 goto out_force;
566 }
567 return nfs_revalidate_inode(server, inode);
568out_force:
569 return __nfs_revalidate_inode(server, inode);
570}
571
572/*
573 * We judge how long we want to trust negative
574 * dentries by looking at the parent inode mtime.
575 *
576 * If parent mtime has changed, we revalidate, else we wait for a
577 * period corresponding to the parent's attribute cache timeout value.
578 */
579static inline
580int nfs_neg_need_reval(struct inode *dir, struct dentry *dentry,
581 struct nameidata *nd)
582{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700583 /* Don't revalidate a negative dentry if we're creating a new file */
Trond Myklebust1d6757f2005-06-07 18:37:01 -0400584 if (nd != NULL && nfs_lookup_check_intent(nd, LOOKUP_CREATE) != 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700585 return 0;
586 return !nfs_check_verifier(dir, dentry);
587}
588
589/*
590 * This is called every time the dcache has a lookup hit,
591 * and we should check whether we can really trust that
592 * lookup.
593 *
594 * NOTE! The hit can be a negative hit too, don't assume
595 * we have an inode!
596 *
597 * If the parent directory is seen to have changed, we throw out the
598 * cached dentry and do a new lookup.
599 */
600static int nfs_lookup_revalidate(struct dentry * dentry, struct nameidata *nd)
601{
602 struct inode *dir;
603 struct inode *inode;
604 struct dentry *parent;
605 int error;
606 struct nfs_fh fhandle;
607 struct nfs_fattr fattr;
608 unsigned long verifier;
609
610 parent = dget_parent(dentry);
611 lock_kernel();
612 dir = parent->d_inode;
613 inode = dentry->d_inode;
614
615 if (!inode) {
616 if (nfs_neg_need_reval(dir, dentry, nd))
617 goto out_bad;
618 goto out_valid;
619 }
620
621 if (is_bad_inode(inode)) {
622 dfprintk(VFS, "nfs_lookup_validate: %s/%s has dud inode\n",
623 dentry->d_parent->d_name.name, dentry->d_name.name);
624 goto out_bad;
625 }
626
627 /* Revalidate parent directory attribute cache */
628 if (nfs_revalidate_inode(NFS_SERVER(dir), dir) < 0)
629 goto out_zap_parent;
630
631 /* Force a full look up iff the parent directory has changed */
632 if (nfs_check_verifier(dir, dentry)) {
633 if (nfs_lookup_verify_inode(inode, nd))
634 goto out_zap_parent;
635 goto out_valid;
636 }
637
638 if (NFS_STALE(inode))
639 goto out_bad;
640
641 verifier = nfs_save_change_attribute(dir);
642 error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, &fhandle, &fattr);
643 if (error)
644 goto out_bad;
645 if (nfs_compare_fh(NFS_FH(inode), &fhandle))
646 goto out_bad;
647 if ((error = nfs_refresh_inode(inode, &fattr)) != 0)
648 goto out_bad;
649
650 nfs_renew_times(dentry);
651 nfs_set_verifier(dentry, verifier);
652 out_valid:
653 unlock_kernel();
654 dput(parent);
655 return 1;
656out_zap_parent:
657 nfs_zap_caches(dir);
658 out_bad:
659 NFS_CACHEINV(dir);
660 if (inode && S_ISDIR(inode->i_mode)) {
661 /* Purge readdir caches. */
662 nfs_zap_caches(inode);
663 /* If we have submounts, don't unhash ! */
664 if (have_submounts(dentry))
665 goto out_valid;
666 shrink_dcache_parent(dentry);
667 }
668 d_drop(dentry);
669 unlock_kernel();
670 dput(parent);
671 return 0;
672}
673
674/*
675 * This is called from dput() when d_count is going to 0.
676 */
677static int nfs_dentry_delete(struct dentry *dentry)
678{
679 dfprintk(VFS, "NFS: dentry_delete(%s/%s, %x)\n",
680 dentry->d_parent->d_name.name, dentry->d_name.name,
681 dentry->d_flags);
682
683 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
684 /* Unhash it, so that ->d_iput() would be called */
685 return 1;
686 }
687 if (!(dentry->d_sb->s_flags & MS_ACTIVE)) {
688 /* Unhash it, so that ancestors of killed async unlink
689 * files will be cleaned up during umount */
690 return 1;
691 }
692 return 0;
693
694}
695
696/*
697 * Called when the dentry loses inode.
698 * We use it to clean up silly-renamed files.
699 */
700static void nfs_dentry_iput(struct dentry *dentry, struct inode *inode)
701{
702 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
703 lock_kernel();
704 inode->i_nlink--;
705 nfs_complete_unlink(dentry);
706 unlock_kernel();
707 }
708 /* When creating a negative dentry, we want to renew d_time */
709 nfs_renew_times(dentry);
710 iput(inode);
711}
712
713struct dentry_operations nfs_dentry_operations = {
714 .d_revalidate = nfs_lookup_revalidate,
715 .d_delete = nfs_dentry_delete,
716 .d_iput = nfs_dentry_iput,
717};
718
Trond Myklebust1d6757f2005-06-07 18:37:01 -0400719/*
720 * Use intent information to check whether or not we're going to do
721 * an O_EXCL create using this path component.
722 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700723static inline
724int nfs_is_exclusive_create(struct inode *dir, struct nameidata *nd)
725{
726 if (NFS_PROTO(dir)->version == 2)
727 return 0;
Trond Myklebust1d6757f2005-06-07 18:37:01 -0400728 if (nd == NULL || nfs_lookup_check_intent(nd, LOOKUP_CREATE) == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700729 return 0;
730 return (nd->intent.open.flags & O_EXCL) != 0;
731}
732
733static struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
734{
735 struct dentry *res;
736 struct inode *inode = NULL;
737 int error;
738 struct nfs_fh fhandle;
739 struct nfs_fattr fattr;
740
741 dfprintk(VFS, "NFS: lookup(%s/%s)\n",
742 dentry->d_parent->d_name.name, dentry->d_name.name);
743
744 res = ERR_PTR(-ENAMETOOLONG);
745 if (dentry->d_name.len > NFS_SERVER(dir)->namelen)
746 goto out;
747
748 res = ERR_PTR(-ENOMEM);
749 dentry->d_op = NFS_PROTO(dir)->dentry_ops;
750
751 lock_kernel();
752 /* Revalidate parent directory attribute cache */
753 error = nfs_revalidate_inode(NFS_SERVER(dir), dir);
754 if (error < 0) {
755 res = ERR_PTR(error);
756 goto out_unlock;
757 }
758
759 /* If we're doing an exclusive create, optimize away the lookup */
760 if (nfs_is_exclusive_create(dir, nd))
761 goto no_entry;
762
763 error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, &fhandle, &fattr);
764 if (error == -ENOENT)
765 goto no_entry;
766 if (error < 0) {
767 res = ERR_PTR(error);
768 goto out_unlock;
769 }
770 res = ERR_PTR(-EACCES);
771 inode = nfs_fhget(dentry->d_sb, &fhandle, &fattr);
772 if (!inode)
773 goto out_unlock;
774no_entry:
775 res = d_add_unique(dentry, inode);
776 if (res != NULL)
777 dentry = res;
778 nfs_renew_times(dentry);
779 nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
780out_unlock:
781 unlock_kernel();
782out:
783 return res;
784}
785
786#ifdef CONFIG_NFS_V4
787static int nfs_open_revalidate(struct dentry *, struct nameidata *);
788
789struct dentry_operations nfs4_dentry_operations = {
790 .d_revalidate = nfs_open_revalidate,
791 .d_delete = nfs_dentry_delete,
792 .d_iput = nfs_dentry_iput,
793};
794
Trond Myklebust1d6757f2005-06-07 18:37:01 -0400795/*
796 * Use intent information to determine whether we need to substitute
797 * the NFSv4-style stateful OPEN for the LOOKUP call
798 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700799static int is_atomic_open(struct inode *dir, struct nameidata *nd)
800{
Trond Myklebust1d6757f2005-06-07 18:37:01 -0400801 if (nd == NULL || nfs_lookup_check_intent(nd, LOOKUP_OPEN) == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700802 return 0;
803 /* NFS does not (yet) have a stateful open for directories */
804 if (nd->flags & LOOKUP_DIRECTORY)
805 return 0;
806 /* Are we trying to write to a read only partition? */
807 if (IS_RDONLY(dir) && (nd->intent.open.flags & (O_CREAT|O_TRUNC|FMODE_WRITE)))
808 return 0;
809 return 1;
810}
811
812static struct dentry *nfs_atomic_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
813{
814 struct dentry *res = NULL;
815 struct inode *inode = NULL;
816 int error;
817
818 /* Check that we are indeed trying to open this file */
819 if (!is_atomic_open(dir, nd))
820 goto no_open;
821
822 if (dentry->d_name.len > NFS_SERVER(dir)->namelen) {
823 res = ERR_PTR(-ENAMETOOLONG);
824 goto out;
825 }
826 dentry->d_op = NFS_PROTO(dir)->dentry_ops;
827
828 /* Let vfs_create() deal with O_EXCL */
829 if (nd->intent.open.flags & O_EXCL)
830 goto no_entry;
831
832 /* Open the file on the server */
833 lock_kernel();
834 /* Revalidate parent directory attribute cache */
835 error = nfs_revalidate_inode(NFS_SERVER(dir), dir);
836 if (error < 0) {
837 res = ERR_PTR(error);
838 goto out;
839 }
840
841 if (nd->intent.open.flags & O_CREAT) {
842 nfs_begin_data_update(dir);
843 inode = nfs4_atomic_open(dir, dentry, nd);
844 nfs_end_data_update(dir);
845 } else
846 inode = nfs4_atomic_open(dir, dentry, nd);
847 unlock_kernel();
848 if (IS_ERR(inode)) {
849 error = PTR_ERR(inode);
850 switch (error) {
851 /* Make a negative dentry */
852 case -ENOENT:
853 inode = NULL;
854 break;
855 /* This turned out not to be a regular file */
856 case -ELOOP:
857 if (!(nd->intent.open.flags & O_NOFOLLOW))
858 goto no_open;
859 /* case -EISDIR: */
860 /* case -EINVAL: */
861 default:
862 res = ERR_PTR(error);
863 goto out;
864 }
865 }
866no_entry:
867 res = d_add_unique(dentry, inode);
868 if (res != NULL)
869 dentry = res;
870 nfs_renew_times(dentry);
871 nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
872out:
873 return res;
874no_open:
875 return nfs_lookup(dir, dentry, nd);
876}
877
878static int nfs_open_revalidate(struct dentry *dentry, struct nameidata *nd)
879{
880 struct dentry *parent = NULL;
881 struct inode *inode = dentry->d_inode;
882 struct inode *dir;
883 unsigned long verifier;
884 int openflags, ret = 0;
885
886 parent = dget_parent(dentry);
887 dir = parent->d_inode;
888 if (!is_atomic_open(dir, nd))
889 goto no_open;
890 /* We can't create new files in nfs_open_revalidate(), so we
891 * optimize away revalidation of negative dentries.
892 */
893 if (inode == NULL)
894 goto out;
895 /* NFS only supports OPEN on regular files */
896 if (!S_ISREG(inode->i_mode))
897 goto no_open;
898 openflags = nd->intent.open.flags;
899 /* We cannot do exclusive creation on a positive dentry */
900 if ((openflags & (O_CREAT|O_EXCL)) == (O_CREAT|O_EXCL))
901 goto no_open;
902 /* We can't create new files, or truncate existing ones here */
903 openflags &= ~(O_CREAT|O_TRUNC);
904
905 /*
906 * Note: we're not holding inode->i_sem and so may be racing with
907 * operations that change the directory. We therefore save the
908 * change attribute *before* we do the RPC call.
909 */
910 lock_kernel();
911 verifier = nfs_save_change_attribute(dir);
912 ret = nfs4_open_revalidate(dir, dentry, openflags);
913 if (!ret)
914 nfs_set_verifier(dentry, verifier);
915 unlock_kernel();
916out:
917 dput(parent);
918 if (!ret)
919 d_drop(dentry);
920 return ret;
921no_open:
922 dput(parent);
923 if (inode != NULL && nfs_have_delegation(inode, FMODE_READ))
924 return 1;
925 return nfs_lookup_revalidate(dentry, nd);
926}
927#endif /* CONFIG_NFSV4 */
928
929static struct dentry *nfs_readdir_lookup(nfs_readdir_descriptor_t *desc)
930{
931 struct dentry *parent = desc->file->f_dentry;
932 struct inode *dir = parent->d_inode;
933 struct nfs_entry *entry = desc->entry;
934 struct dentry *dentry, *alias;
935 struct qstr name = {
936 .name = entry->name,
937 .len = entry->len,
938 };
939 struct inode *inode;
940
941 switch (name.len) {
942 case 2:
943 if (name.name[0] == '.' && name.name[1] == '.')
944 return dget_parent(parent);
945 break;
946 case 1:
947 if (name.name[0] == '.')
948 return dget(parent);
949 }
950 name.hash = full_name_hash(name.name, name.len);
951 dentry = d_lookup(parent, &name);
952 if (dentry != NULL)
953 return dentry;
954 if (!desc->plus || !(entry->fattr->valid & NFS_ATTR_FATTR))
955 return NULL;
956 /* Note: caller is already holding the dir->i_sem! */
957 dentry = d_alloc(parent, &name);
958 if (dentry == NULL)
959 return NULL;
960 dentry->d_op = NFS_PROTO(dir)->dentry_ops;
961 inode = nfs_fhget(dentry->d_sb, entry->fh, entry->fattr);
962 if (!inode) {
963 dput(dentry);
964 return NULL;
965 }
966 alias = d_add_unique(dentry, inode);
967 if (alias != NULL) {
968 dput(dentry);
969 dentry = alias;
970 }
971 nfs_renew_times(dentry);
972 nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
973 return dentry;
974}
975
976/*
977 * Code common to create, mkdir, and mknod.
978 */
979int nfs_instantiate(struct dentry *dentry, struct nfs_fh *fhandle,
980 struct nfs_fattr *fattr)
981{
982 struct inode *inode;
983 int error = -EACCES;
984
985 /* We may have been initialized further down */
986 if (dentry->d_inode)
987 return 0;
988 if (fhandle->size == 0) {
989 struct inode *dir = dentry->d_parent->d_inode;
990 error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr);
991 if (error)
992 goto out_err;
993 }
994 if (!(fattr->valid & NFS_ATTR_FATTR)) {
995 struct nfs_server *server = NFS_SB(dentry->d_sb);
996 error = server->rpc_ops->getattr(server, fhandle, fattr);
997 if (error < 0)
998 goto out_err;
999 }
1000 error = -ENOMEM;
1001 inode = nfs_fhget(dentry->d_sb, fhandle, fattr);
1002 if (inode == NULL)
1003 goto out_err;
1004 d_instantiate(dentry, inode);
1005 return 0;
1006out_err:
1007 d_drop(dentry);
1008 return error;
1009}
1010
1011/*
1012 * Following a failed create operation, we drop the dentry rather
1013 * than retain a negative dentry. This avoids a problem in the event
1014 * that the operation succeeded on the server, but an error in the
1015 * reply path made it appear to have failed.
1016 */
1017static int nfs_create(struct inode *dir, struct dentry *dentry, int mode,
1018 struct nameidata *nd)
1019{
1020 struct iattr attr;
1021 int error;
1022 int open_flags = 0;
1023
1024 dfprintk(VFS, "NFS: create(%s/%ld, %s\n", dir->i_sb->s_id,
1025 dir->i_ino, dentry->d_name.name);
1026
1027 attr.ia_mode = mode;
1028 attr.ia_valid = ATTR_MODE;
1029
1030 if (nd && (nd->flags & LOOKUP_CREATE))
1031 open_flags = nd->intent.open.flags;
1032
1033 lock_kernel();
1034 nfs_begin_data_update(dir);
1035 error = NFS_PROTO(dir)->create(dir, dentry, &attr, open_flags);
1036 nfs_end_data_update(dir);
1037 if (error != 0)
1038 goto out_err;
1039 nfs_renew_times(dentry);
1040 nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
1041 unlock_kernel();
1042 return 0;
1043out_err:
1044 unlock_kernel();
1045 d_drop(dentry);
1046 return error;
1047}
1048
1049/*
1050 * See comments for nfs_proc_create regarding failed operations.
1051 */
1052static int
1053nfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t rdev)
1054{
1055 struct iattr attr;
1056 int status;
1057
1058 dfprintk(VFS, "NFS: mknod(%s/%ld, %s\n", dir->i_sb->s_id,
1059 dir->i_ino, dentry->d_name.name);
1060
1061 if (!new_valid_dev(rdev))
1062 return -EINVAL;
1063
1064 attr.ia_mode = mode;
1065 attr.ia_valid = ATTR_MODE;
1066
1067 lock_kernel();
1068 nfs_begin_data_update(dir);
1069 status = NFS_PROTO(dir)->mknod(dir, dentry, &attr, rdev);
1070 nfs_end_data_update(dir);
1071 if (status != 0)
1072 goto out_err;
1073 nfs_renew_times(dentry);
1074 nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
1075 unlock_kernel();
1076 return 0;
1077out_err:
1078 unlock_kernel();
1079 d_drop(dentry);
1080 return status;
1081}
1082
1083/*
1084 * See comments for nfs_proc_create regarding failed operations.
1085 */
1086static int nfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
1087{
1088 struct iattr attr;
1089 int error;
1090
1091 dfprintk(VFS, "NFS: mkdir(%s/%ld, %s\n", dir->i_sb->s_id,
1092 dir->i_ino, dentry->d_name.name);
1093
1094 attr.ia_valid = ATTR_MODE;
1095 attr.ia_mode = mode | S_IFDIR;
1096
1097 lock_kernel();
1098 nfs_begin_data_update(dir);
1099 error = NFS_PROTO(dir)->mkdir(dir, dentry, &attr);
1100 nfs_end_data_update(dir);
1101 if (error != 0)
1102 goto out_err;
1103 nfs_renew_times(dentry);
1104 nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
1105 unlock_kernel();
1106 return 0;
1107out_err:
1108 d_drop(dentry);
1109 unlock_kernel();
1110 return error;
1111}
1112
1113static int nfs_rmdir(struct inode *dir, struct dentry *dentry)
1114{
1115 int error;
1116
1117 dfprintk(VFS, "NFS: rmdir(%s/%ld, %s\n", dir->i_sb->s_id,
1118 dir->i_ino, dentry->d_name.name);
1119
1120 lock_kernel();
1121 nfs_begin_data_update(dir);
1122 error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name);
1123 /* Ensure the VFS deletes this inode */
1124 if (error == 0 && dentry->d_inode != NULL)
1125 dentry->d_inode->i_nlink = 0;
1126 nfs_end_data_update(dir);
1127 unlock_kernel();
1128
1129 return error;
1130}
1131
1132static int nfs_sillyrename(struct inode *dir, struct dentry *dentry)
1133{
1134 static unsigned int sillycounter;
1135 const int i_inosize = sizeof(dir->i_ino)*2;
1136 const int countersize = sizeof(sillycounter)*2;
1137 const int slen = sizeof(".nfs") + i_inosize + countersize - 1;
1138 char silly[slen+1];
1139 struct qstr qsilly;
1140 struct dentry *sdentry;
1141 int error = -EIO;
1142
1143 dfprintk(VFS, "NFS: silly-rename(%s/%s, ct=%d)\n",
1144 dentry->d_parent->d_name.name, dentry->d_name.name,
1145 atomic_read(&dentry->d_count));
1146
1147#ifdef NFS_PARANOIA
1148if (!dentry->d_inode)
1149printk("NFS: silly-renaming %s/%s, negative dentry??\n",
1150dentry->d_parent->d_name.name, dentry->d_name.name);
1151#endif
1152 /*
1153 * We don't allow a dentry to be silly-renamed twice.
1154 */
1155 error = -EBUSY;
1156 if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
1157 goto out;
1158
1159 sprintf(silly, ".nfs%*.*lx",
1160 i_inosize, i_inosize, dentry->d_inode->i_ino);
1161
1162 sdentry = NULL;
1163 do {
1164 char *suffix = silly + slen - countersize;
1165
1166 dput(sdentry);
1167 sillycounter++;
1168 sprintf(suffix, "%*.*x", countersize, countersize, sillycounter);
1169
1170 dfprintk(VFS, "trying to rename %s to %s\n",
1171 dentry->d_name.name, silly);
1172
1173 sdentry = lookup_one_len(silly, dentry->d_parent, slen);
1174 /*
1175 * N.B. Better to return EBUSY here ... it could be
1176 * dangerous to delete the file while it's in use.
1177 */
1178 if (IS_ERR(sdentry))
1179 goto out;
1180 } while(sdentry->d_inode != NULL); /* need negative lookup */
1181
1182 qsilly.name = silly;
1183 qsilly.len = strlen(silly);
1184 nfs_begin_data_update(dir);
1185 if (dentry->d_inode) {
1186 nfs_begin_data_update(dentry->d_inode);
1187 error = NFS_PROTO(dir)->rename(dir, &dentry->d_name,
1188 dir, &qsilly);
1189 nfs_end_data_update(dentry->d_inode);
1190 } else
1191 error = NFS_PROTO(dir)->rename(dir, &dentry->d_name,
1192 dir, &qsilly);
1193 nfs_end_data_update(dir);
1194 if (!error) {
1195 nfs_renew_times(dentry);
1196 nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
1197 d_move(dentry, sdentry);
1198 error = nfs_async_unlink(dentry);
1199 /* If we return 0 we don't unlink */
1200 }
1201 dput(sdentry);
1202out:
1203 return error;
1204}
1205
1206/*
1207 * Remove a file after making sure there are no pending writes,
1208 * and after checking that the file has only one user.
1209 *
1210 * We invalidate the attribute cache and free the inode prior to the operation
1211 * to avoid possible races if the server reuses the inode.
1212 */
1213static int nfs_safe_remove(struct dentry *dentry)
1214{
1215 struct inode *dir = dentry->d_parent->d_inode;
1216 struct inode *inode = dentry->d_inode;
1217 int error = -EBUSY;
1218
1219 dfprintk(VFS, "NFS: safe_remove(%s/%s)\n",
1220 dentry->d_parent->d_name.name, dentry->d_name.name);
1221
1222 /* If the dentry was sillyrenamed, we simply call d_delete() */
1223 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
1224 error = 0;
1225 goto out;
1226 }
1227
1228 nfs_begin_data_update(dir);
1229 if (inode != NULL) {
1230 nfs_begin_data_update(inode);
1231 error = NFS_PROTO(dir)->remove(dir, &dentry->d_name);
1232 /* The VFS may want to delete this inode */
1233 if (error == 0)
1234 inode->i_nlink--;
1235 nfs_end_data_update(inode);
1236 } else
1237 error = NFS_PROTO(dir)->remove(dir, &dentry->d_name);
1238 nfs_end_data_update(dir);
1239out:
1240 return error;
1241}
1242
1243/* We do silly rename. In case sillyrename() returns -EBUSY, the inode
1244 * belongs to an active ".nfs..." file and we return -EBUSY.
1245 *
1246 * If sillyrename() returns 0, we do nothing, otherwise we unlink.
1247 */
1248static int nfs_unlink(struct inode *dir, struct dentry *dentry)
1249{
1250 int error;
1251 int need_rehash = 0;
1252
1253 dfprintk(VFS, "NFS: unlink(%s/%ld, %s)\n", dir->i_sb->s_id,
1254 dir->i_ino, dentry->d_name.name);
1255
1256 lock_kernel();
1257 spin_lock(&dcache_lock);
1258 spin_lock(&dentry->d_lock);
1259 if (atomic_read(&dentry->d_count) > 1) {
1260 spin_unlock(&dentry->d_lock);
1261 spin_unlock(&dcache_lock);
1262 error = nfs_sillyrename(dir, dentry);
1263 unlock_kernel();
1264 return error;
1265 }
1266 if (!d_unhashed(dentry)) {
1267 __d_drop(dentry);
1268 need_rehash = 1;
1269 }
1270 spin_unlock(&dentry->d_lock);
1271 spin_unlock(&dcache_lock);
1272 error = nfs_safe_remove(dentry);
1273 if (!error) {
1274 nfs_renew_times(dentry);
1275 nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
1276 } else if (need_rehash)
1277 d_rehash(dentry);
1278 unlock_kernel();
1279 return error;
1280}
1281
1282static int
1283nfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
1284{
1285 struct iattr attr;
1286 struct nfs_fattr sym_attr;
1287 struct nfs_fh sym_fh;
1288 struct qstr qsymname;
1289 int error;
1290
1291 dfprintk(VFS, "NFS: symlink(%s/%ld, %s, %s)\n", dir->i_sb->s_id,
1292 dir->i_ino, dentry->d_name.name, symname);
1293
1294#ifdef NFS_PARANOIA
1295if (dentry->d_inode)
1296printk("nfs_proc_symlink: %s/%s not negative!\n",
1297dentry->d_parent->d_name.name, dentry->d_name.name);
1298#endif
1299 /*
1300 * Fill in the sattr for the call.
1301 * Note: SunOS 4.1.2 crashes if the mode isn't initialized!
1302 */
1303 attr.ia_valid = ATTR_MODE;
1304 attr.ia_mode = S_IFLNK | S_IRWXUGO;
1305
1306 qsymname.name = symname;
1307 qsymname.len = strlen(symname);
1308
1309 lock_kernel();
1310 nfs_begin_data_update(dir);
1311 error = NFS_PROTO(dir)->symlink(dir, &dentry->d_name, &qsymname,
1312 &attr, &sym_fh, &sym_attr);
1313 nfs_end_data_update(dir);
1314 if (!error) {
1315 error = nfs_instantiate(dentry, &sym_fh, &sym_attr);
1316 } else {
1317 if (error == -EEXIST)
1318 printk("nfs_proc_symlink: %s/%s already exists??\n",
1319 dentry->d_parent->d_name.name, dentry->d_name.name);
1320 d_drop(dentry);
1321 }
1322 unlock_kernel();
1323 return error;
1324}
1325
1326static int
1327nfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
1328{
1329 struct inode *inode = old_dentry->d_inode;
1330 int error;
1331
1332 dfprintk(VFS, "NFS: link(%s/%s -> %s/%s)\n",
1333 old_dentry->d_parent->d_name.name, old_dentry->d_name.name,
1334 dentry->d_parent->d_name.name, dentry->d_name.name);
1335
1336 /*
1337 * Drop the dentry in advance to force a new lookup.
1338 * Since nfs_proc_link doesn't return a file handle,
1339 * we can't use the existing dentry.
1340 */
1341 lock_kernel();
1342 d_drop(dentry);
1343
1344 nfs_begin_data_update(dir);
1345 nfs_begin_data_update(inode);
1346 error = NFS_PROTO(dir)->link(inode, dir, &dentry->d_name);
1347 nfs_end_data_update(inode);
1348 nfs_end_data_update(dir);
1349 unlock_kernel();
1350 return error;
1351}
1352
1353/*
1354 * RENAME
1355 * FIXME: Some nfsds, like the Linux user space nfsd, may generate a
1356 * different file handle for the same inode after a rename (e.g. when
1357 * moving to a different directory). A fail-safe method to do so would
1358 * be to look up old_dir/old_name, create a link to new_dir/new_name and
1359 * rename the old file using the sillyrename stuff. This way, the original
1360 * file in old_dir will go away when the last process iput()s the inode.
1361 *
1362 * FIXED.
1363 *
1364 * It actually works quite well. One needs to have the possibility for
1365 * at least one ".nfs..." file in each directory the file ever gets
1366 * moved or linked to which happens automagically with the new
1367 * implementation that only depends on the dcache stuff instead of
1368 * using the inode layer
1369 *
1370 * Unfortunately, things are a little more complicated than indicated
1371 * above. For a cross-directory move, we want to make sure we can get
1372 * rid of the old inode after the operation. This means there must be
1373 * no pending writes (if it's a file), and the use count must be 1.
1374 * If these conditions are met, we can drop the dentries before doing
1375 * the rename.
1376 */
1377static int nfs_rename(struct inode *old_dir, struct dentry *old_dentry,
1378 struct inode *new_dir, struct dentry *new_dentry)
1379{
1380 struct inode *old_inode = old_dentry->d_inode;
1381 struct inode *new_inode = new_dentry->d_inode;
1382 struct dentry *dentry = NULL, *rehash = NULL;
1383 int error = -EBUSY;
1384
1385 /*
1386 * To prevent any new references to the target during the rename,
1387 * we unhash the dentry and free the inode in advance.
1388 */
1389 lock_kernel();
1390 if (!d_unhashed(new_dentry)) {
1391 d_drop(new_dentry);
1392 rehash = new_dentry;
1393 }
1394
1395 dfprintk(VFS, "NFS: rename(%s/%s -> %s/%s, ct=%d)\n",
1396 old_dentry->d_parent->d_name.name, old_dentry->d_name.name,
1397 new_dentry->d_parent->d_name.name, new_dentry->d_name.name,
1398 atomic_read(&new_dentry->d_count));
1399
1400 /*
1401 * First check whether the target is busy ... we can't
1402 * safely do _any_ rename if the target is in use.
1403 *
1404 * For files, make a copy of the dentry and then do a
1405 * silly-rename. If the silly-rename succeeds, the
1406 * copied dentry is hashed and becomes the new target.
1407 */
1408 if (!new_inode)
1409 goto go_ahead;
1410 if (S_ISDIR(new_inode->i_mode))
1411 goto out;
1412 else if (atomic_read(&new_dentry->d_count) > 2) {
1413 int err;
1414 /* copy the target dentry's name */
1415 dentry = d_alloc(new_dentry->d_parent,
1416 &new_dentry->d_name);
1417 if (!dentry)
1418 goto out;
1419
1420 /* silly-rename the existing target ... */
1421 err = nfs_sillyrename(new_dir, new_dentry);
1422 if (!err) {
1423 new_dentry = rehash = dentry;
1424 new_inode = NULL;
1425 /* instantiate the replacement target */
1426 d_instantiate(new_dentry, NULL);
1427 } else if (atomic_read(&new_dentry->d_count) > 1) {
1428 /* dentry still busy? */
1429#ifdef NFS_PARANOIA
1430 printk("nfs_rename: target %s/%s busy, d_count=%d\n",
1431 new_dentry->d_parent->d_name.name,
1432 new_dentry->d_name.name,
1433 atomic_read(&new_dentry->d_count));
1434#endif
1435 goto out;
1436 }
1437 }
1438
1439go_ahead:
1440 /*
1441 * ... prune child dentries and writebacks if needed.
1442 */
1443 if (atomic_read(&old_dentry->d_count) > 1) {
1444 nfs_wb_all(old_inode);
1445 shrink_dcache_parent(old_dentry);
1446 }
1447
1448 if (new_inode)
1449 d_delete(new_dentry);
1450
1451 nfs_begin_data_update(old_dir);
1452 nfs_begin_data_update(new_dir);
1453 nfs_begin_data_update(old_inode);
1454 error = NFS_PROTO(old_dir)->rename(old_dir, &old_dentry->d_name,
1455 new_dir, &new_dentry->d_name);
1456 nfs_end_data_update(old_inode);
1457 nfs_end_data_update(new_dir);
1458 nfs_end_data_update(old_dir);
1459out:
1460 if (rehash)
1461 d_rehash(rehash);
1462 if (!error) {
1463 if (!S_ISDIR(old_inode->i_mode))
1464 d_move(old_dentry, new_dentry);
1465 nfs_renew_times(new_dentry);
1466 nfs_set_verifier(new_dentry, nfs_save_change_attribute(new_dir));
1467 }
1468
1469 /* new dentry created? */
1470 if (dentry)
1471 dput(dentry);
1472 unlock_kernel();
1473 return error;
1474}
1475
1476int nfs_access_get_cached(struct inode *inode, struct rpc_cred *cred, struct nfs_access_entry *res)
1477{
1478 struct nfs_access_entry *cache = &NFS_I(inode)->cache_access;
1479
1480 if (cache->cred != cred
1481 || time_after(jiffies, cache->jiffies + NFS_ATTRTIMEO(inode))
1482 || (NFS_FLAGS(inode) & NFS_INO_INVALID_ACCESS))
1483 return -ENOENT;
1484 memcpy(res, cache, sizeof(*res));
1485 return 0;
1486}
1487
1488void nfs_access_add_cache(struct inode *inode, struct nfs_access_entry *set)
1489{
1490 struct nfs_access_entry *cache = &NFS_I(inode)->cache_access;
1491
1492 if (cache->cred != set->cred) {
1493 if (cache->cred)
1494 put_rpccred(cache->cred);
1495 cache->cred = get_rpccred(set->cred);
1496 }
1497 NFS_FLAGS(inode) &= ~NFS_INO_INVALID_ACCESS;
1498 cache->jiffies = set->jiffies;
1499 cache->mask = set->mask;
1500}
1501
1502static int nfs_do_access(struct inode *inode, struct rpc_cred *cred, int mask)
1503{
1504 struct nfs_access_entry cache;
1505 int status;
1506
1507 status = nfs_access_get_cached(inode, cred, &cache);
1508 if (status == 0)
1509 goto out;
1510
1511 /* Be clever: ask server to check for all possible rights */
1512 cache.mask = MAY_EXEC | MAY_WRITE | MAY_READ;
1513 cache.cred = cred;
1514 cache.jiffies = jiffies;
1515 status = NFS_PROTO(inode)->access(inode, &cache);
1516 if (status != 0)
1517 return status;
1518 nfs_access_add_cache(inode, &cache);
1519out:
1520 if ((cache.mask & mask) == mask)
1521 return 0;
1522 return -EACCES;
1523}
1524
1525int nfs_permission(struct inode *inode, int mask, struct nameidata *nd)
1526{
1527 struct rpc_cred *cred;
1528 int res = 0;
1529
1530 if (mask == 0)
1531 goto out;
1532 /* Is this sys_access() ? */
1533 if (nd != NULL && (nd->flags & LOOKUP_ACCESS))
1534 goto force_lookup;
1535
1536 switch (inode->i_mode & S_IFMT) {
1537 case S_IFLNK:
1538 goto out;
1539 case S_IFREG:
1540 /* NFSv4 has atomic_open... */
1541 if (nfs_server_capable(inode, NFS_CAP_ATOMIC_OPEN)
1542 && nd != NULL
1543 && (nd->flags & LOOKUP_OPEN))
1544 goto out;
1545 break;
1546 case S_IFDIR:
1547 /*
1548 * Optimize away all write operations, since the server
1549 * will check permissions when we perform the op.
1550 */
1551 if ((mask & MAY_WRITE) && !(mask & MAY_READ))
1552 goto out;
1553 }
1554
1555force_lookup:
1556 lock_kernel();
1557
1558 if (!NFS_PROTO(inode)->access)
1559 goto out_notsup;
1560
1561 cred = rpcauth_lookupcred(NFS_CLIENT(inode)->cl_auth, 0);
1562 if (!IS_ERR(cred)) {
1563 res = nfs_do_access(inode, cred, mask);
1564 put_rpccred(cred);
1565 } else
1566 res = PTR_ERR(cred);
1567 unlock_kernel();
1568out:
1569 return res;
1570out_notsup:
1571 res = nfs_revalidate_inode(NFS_SERVER(inode), inode);
1572 if (res == 0)
1573 res = generic_permission(inode, mask, NULL);
1574 unlock_kernel();
1575 return res;
1576}
1577
1578/*
1579 * Local variables:
1580 * version-control: t
1581 * kept-new-versions: 5
1582 * End:
1583 */